solve

 sudoku

Work down boxes 2, 5 & 8 filling in all the possible values for each empty cell.

This finds 4 and therefore 9 in box 2 leaving only 8 & 3 for the last two cells

As we have found 4 in box 2 above, c5/r6 must be 2.
Therefore the last two cells in box 5 must be a 3 or 4.

It follows that row 5 in box 6 cannot have a 3 or 4 so it must be 5. The last cell in box 6 at c9r6 is therefore 4.